The Sample Registration System (SRS) is a large-scale demographic survey and a dual record system concept, not a legislative act or institution, designed to provide reliable annual estimates of fertility and mortality indicators in India. It was initiated on a pilot basis in 1964-1965 by the Office of the Registrar General, India (RGI), and became fully operational during 1969-1970. The SRS was created because the existing system of birth and death registration was voluntary and incomplete, leading to a lack of reliable vital statistics for planning purposes.
The system works through a dual record system mechanism. The field investigation consists of two independent processes: a continuous enumeration of births and deaths in selected sample units by resident part-time enumerators, and an independent retrospective survey conducted every six months by SRS supervisors. The data from these two sources are matched, and any unmatched or partially matched events are re-verified in the field to ensure an unduplicated count of vital events.
The SRS is a primary source of vital statistics, connecting it to the Civil Registration System (CRS), the decennial Census, and the National Family Health Surveys (NFHS). The RGI, which conducts the SRS, is also responsible for implementing the Registration of Births and Deaths (RBD) Act, 1969. Recent changes include the merger of the Survey of Causes of Death with the SRS in 1999, which uses a verbal autopsy method to ascertain causes of death. Furthermore, the RGI has introduced an automated procedure using a mobile app for data collection by enumerators and supervisors. The SRS sample units are typically retained for about ten years, based on the latest census frame.